TOFG-all

Selecting & Using Cover Crops

Unit 1.6 | Part 1 – 275
Instructor’s Demonstration Outline

Demonstration: How to Estimate the Nitrogen

Contribution of a Cover Crop

for the instructor

OVERVIEW

Through this hand-on field

demonstration and discussion,

students will learn how to estimate

the nitrogen contribution of a

cover crop for nutrient budgeting

purposes. (See Unit 1.11: Reading

and Interpreting Soil Test Reports

for more on nutrient budgeting.)

PREPARATION AND MATERIALS

1. If possible, students should have received the lecture
   portion of this unit covering the biology and functions
   of cover crops in agricultural systems.


2. Necessary tools and equipment: greenhouse or oven (for
   drying cover crops), clippers, measuring tape/stick or
   measuring frame, scale.


3. A mature stand of actively growing cover crops.


4. Demonstrate procedure and then assign each small
   group the tasks of cutting, drying, weighing, and
   calculating the nitrogen contribution of the cover crops
   (in total N lb/ac).

PREPARATION TIME

1 hour

DEMONSTRATION AND DISCUSSION TIME

(2) 2 hour periods

DEMONSTRATION OUTLINE

A. Discuss and demonstrate the collection and calculation

of the above-ground weight for a given area of cover crop

1. Demonstrate taking a number of samples from the field:
   how to use a yardstick or frame to measure area to be
   sampled, and how to clip the cover crops at the ground
   level


2. Demonstrate and discuss techniques for sun drying the
   fresh cover crop material in the greenhouse or in the
   oven (150ºF) until “crunchy” or brittle